(ANSA) - BELGRADE, 10 OTT - A protest took place today in the northern (Serbian) sector of Kosovska Mitrovica in response to the arrest of a Serbian politician yesterday. Aleksandar Arsenijevic, leader of the Serbian Democracy party, was arrested in northern Mitrovica by Kosovo police for loudly protesting against the city's mayor, an ethnic Albanian politician elected in last year's local elections, which Serbs largely boycotted. Arsenijevic had previously been detained and warned for similar protests against non-Serbian local officials, but yesterday, the police arrested him and placed him in custody. Today's protest, which featured whistles and banners against Pristina's leadership, was peaceful, and local authorities reported no incidents. Kosovska Mitrovica, divided by the Ibar River into a northern Serbian sector and a southern Albanian one, is located in the northern part of Kosovo, where the population is predominantly Serbian. Northern Mitrovica is one of the four largest municipalities with a Serbian majority, along with Zvecan, Zubin Potok, and Leposavic. (ANSA).